> From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] > Sent: Thursday, August 21, 2014 12:16 PM > > On Thu, 21 Aug 2014, Paul Zimmerman wrote: > > > AFAIK, it has always been a requirement that usb_ep_dequeue() release > > the data buffer and call the urb's completion routine before it returns. > > Hmmm. I don't know if that really has been a requirement, but it does > seem to be true in the UDC drivers I'm familiar with. > > > Quite a few of the function drivers depend on that, after the call to > > usb_ep_dequeue() they immediately free the data buffer. So if it's not > > explicitly documented like that, it should be. > > Okay, would you like to write a documentation patch? Something like this? I didn't find any references to usp_ep_dequeue() under Documentation/, so I guess the only place is the kerneldoc in the header. I also fixed up some strange capitalization in the existing text while I was there. If this looks OK to you I will send a proper patch submission to Felipe. [PATCH] usb: gadget: document a usb_ep_dequeue() requirement Document the requirement that the request be dequeued and its completion routine called before usb_ep_dequeue() returns. diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index c3a6185..c540557 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -345,12 +345,13 @@ static inline int usb_ep_queue(struct usb_ep *ep, * @ep:the endpoint associated with the request * @req:the request being canceled * - * if the request is still active on the endpoint, it is dequeued and its + * If the request is still active on the endpoint, it is dequeued and its * completion routine is called (with status -ECONNRESET); else a negative - * error code is returned. + * error code is returned. This is guaranteed to happen before the call to + * usb_ep_dequeue() returns. * - * note that some hardware can't clear out write fifos (to unlink the request - * at the head of the queue) except as part of disconnecting from usb. such + * Note that some hardware can't clear out write fifos (to unlink the request + * at the head of the queue) except as part of disconnecting from usb. Such * restrictions prevent drivers from supporting configuration changes, * even to configuration zero (a "chapter 9" requirement). */ -- Paul -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
